Capsule holders

Capsule holders are typically located circumferentially around the core to provide assurance that test specimens and monitors duplicate, as closely as possible, the irradiation history of the reactor vessel, including neutron spectrum, temperature history and maximum neutron fluence. Holders must be designed to avoid interference with in-service inspections required by Section XI of the ASME Code (ASME, 2010a). Most surveillance programs have the capsules located between the thermal shield and the reactor vessel wall with the vertical center at the core mid-plane. C-E, General Electric and B W designs have the holders attached directly to... 

A typical capsule assembly, illustrated in Figure 5.3-1, consists of a series of three specimen compartments, connected by wedge couplings, and a lock assembly. Each compartment enclosure of the capsule assembly is internally supported by the surveillance specimens and is externally pressure tested to 3125 psi during final fabrication. The wedge couplings also serve as end caps for the specimen compartments and position the compartments within the capsule holders which are attached to the reactor vessel cladding. The lock assemblies fix the locations of the... 

The capsule assemblies are placed in capsule holders positioned circumferentially about the core at locations which include the regions of maximum flux. Figure 5.3-4 presents the typical exposure locations for the capsule assemblies. 

All capsule assemblies are inserted into their respective capsule holders during the final reactor assembly operation. The design also permits the remote installation of replacement capsule assemblies. The capsule holders are welded to the vessel cladding on the inside surface, and the welds are subject to inspection according to the requirements for permanent structural attachments as given in the ASME Code, Sections III and XI. 

The reactor components and the assembled reactor are shown in Figure 1. Components of the reactor include (1) capsule holder, (2) flywheel, (3) rotary feedthrough, (4) grid and screen, (5) pressure transducer, and (6) thermocouple. The internal volume was 415 cc and held a 24 cc capsule. The reactor was made of 304 stainless steel and weighed about 35 pounds. Specifications are presented in Table 1 describing the upper limits of temperature and pressure for the major components. 

The capsule holder contained the activated catalyst in a sealed glass capsule at the start of the test. The reaction was initiated by manually rotating the holder 180 degrees releasing the capsule into the flywheel. 

The surveillance capsule holder is a stainless steel container, which houses RPV surveillance specimen capsules used to monitor embrittlement due to neutron irradiation of the vessel shell. A bracket holds the surveillance capsule holder to the vessel wall. Capsule holders are removed with RPV surveillance specimens on a pre-planned basis in accordance with the plant surveillance plan. 

Surveillance Capsule Holder Not considered to be important to safety... 

Although the patent holders at first sold both filled and empty soft gelatin capsules, the sale of empty shells was discontinued after 1837 [2]. However, the demand that had been created for the empty capsules... 

This is usually caused by violent cycling of the SRV many times a second. In many instances, this causes the bellows flange to be sheared from the bellows capsule. This way the bellows can even become detached from the disc holder. 

However, great care must be taken in choosing an appropriate sample holder and a suitable sample geometry.9 Cylindrical capsules machined from high-purity PTFE, enclosed in long polyethylene straws, allow the measurement of compressed polycrystalline samples or even solutions. Polycrystalline samples need to be pulverized so that preferential orientation can be avoided. The sample should be placed into a cylindrically shaped sample holder. Air-sensitive compounds can be sealed in small tubes from synthetic quartz glass. The field- and temperature-dependent contribution of the sample holder must be known precisely. 

Fig. 3 Schematic diagram of auger filling system (Model No. 8) (A) powder hopper (B) stirrer arm (C) auger (D) body ring holder (E) turntable and (F) capsule carrying rings.

Laminar flow conditions are typically used for tablets, hard gelatin capsules, powders, and granules. Suppositories and soft gelatin capsules are placed in the cell without beads for turbulent flow. Nicolaides, Hempenstall, and Reppas have reported differences in the dissolution rate of a poorly soluble drug, tiaglitazone, from an immediate-release (IR) tablet formulation based on the presence or absence of a tablet holder and/or beads in the flow-through cell. 

Lodder, R.A. Sample Holders or Reflectors for Intact Capsules and Tablets and for Liquid Microcells for Use in Near-Infrared Reflectance Spectrophotometers. US Patent 165,751, November 21, 1989. 

Thermolysis of solid la, lb 1) in an aluminum capsule, 1 mg of la or lb were sealed in a cylindrical, air-tight, pressure-resistant, aluminum sample-holder (volume 30 mm ) and were then decomposed in a DSC calorimeter at a constant heating rate (10 °C/min). 

Osaka Automatic Machine Co. produce a fluidisation machine which is an automatic dependent filling machine. The capsule body in its holder passes below the powder hopper. The powder is fluidised by a vibrating plate to aid flow into the capsule body. The capsule body can be held below the hopper base so that it becomes overfilled, and the fill can be compressed into the capsule by raising the body against a flat surface prior to the capsule closing. This technique has not been the subject of published formulation studies, but appropriate flow properties and lubrication are likely to be required. 

Auger or Screw Method. This was the first mechanism used in industrial-scale machines, although the dosator and piston tamp mechanisms have now largely superseded it. The capsule body in its holder passes beneath the powder hopper on a turntable. The powder is fed into the capsule body by a revolving archimedian screw. The auger rotates at a constant rate so the fill weight is related to the duration of filling that is related to the speed of rotation of the turntable. 

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